Method of treating mechanical wood pulp



July 5, 1932. P. KLEM METHOD OF TREATING MECHANICAL WOOD PULP M. Z .fi rilui|$ n L v E w v l y w 2 QW W tl atented duly 5, E932 meant ti r, Y E Q FEQE PER ELEM, 0F @SLO, NORWAY METHOD OF TREATING MECHANICAL WOQD PULP Application filed. November 30, 1829, Serial No. 210,665, and in Norway November 30, 1928.

This invention relates to the manufacture of wood pulp and wood pulp products and has for it object a method of treating mechanical wood pulp, whereby the usefullness of the pulp as a constituent of paper as well as for other purposes is increased.

The invention is applicable to wood pulp of any kind, whether it has been subjected or not to a chemical treatment.

An important feature of the method according to the invention consists therein that the pulp is subjected to a treatment, by which that part of the pulp which is composed of fibres, fibrillae and fibre bundles is given altered properties, comprising an increased flexibility and improved power of felting.

The efiect aimed at may be brought about. by mechanical working or by the influence of chemicals or by mechanical as well as chemical means.

The result aimed atcan for example be attained by separating the pulp, subsequent to its having been subjected to the usual hand ling in suitable apparatus, into two portions according to the size of particles, whereupon one or both (or all) of said portions are each separately subjected to a special treatment, after which the portions may again be united or used separately. This special treatment may with respect to the coarser particles, for example, consist in a mechanica working resulting in opening (loosening) and softening the fibres and making same pliable or flexible.

This special treatment may also be applied to the fibres at an earlier stage in the operations of producing the pulp, for example previous to the usual screening before or aftter separation of the so-called mill pulp or chips.

Instead of mixing the separately treated fibre grades and flour, each of the products may also be further independently and separately worked, to be made applicable for difierent uses.

Whether the groups of fibres are mixed with one another entirely or in part or not at all, they may also be mixed with other substances of any kind before they are brought into the final condition for sale or use.

In the accompanying drawing,

Fig. 1 illustrates diagrammatically an embodiment of the treatment according to the invention.

Fig. 2 illustrates a modified arrangement.

In the example illustrated in Fig. 1, Ais the grindstone, B is a coarse screening apparatus (bull screen or knotter) from which the coarser particles (slivers, splinters, knots) leave at 1, while the rest passes through 2 into the ordinary sorting system C. .The sorted Wood pulp thereupon passes through a system of sorting devices at D, wherein the pulp is separated into the desired number of groups, each containing the desired percentages of the various particles. (This may be designated as the screening system for flour and fibre.)

The various grades or groups of pulp leave this-system at 8, 4, 8 and 5. The separated groups are at E subjected to further treat- 761 ment and leave at 6 to be further worked or mixed with other substances or with other groups of pulp. Other substances, such as cellulose (chemical pulp) or china clay from Ur may be introduced into any of the grades of pulp through 9.

Tn Fig. 2, his the rindstone, B the coarse screening device, and is a sorting apparatus (screen) receivlng screened pulp from B. The finer particles (flour) leave this screen so through 16, while the coarser particles (fibres and chips) are passed into a further screen L, in which the chips are separated from the rest (which are in themselves comparatively coarse particles). The chips are through 15 passed to a refiner to be further disintegrated. The coarser particles pass through 14: and 17 into a sorting screen M. The fine particles from M leave through 18 and unite with the finer particles from 16. The coarser particles from M pass into a further screen N, wherein the remainder of chips is separated ed" at '19. The finer particles pass through a thickener U and into a grinding apparatus (such as a Jordan mill or heater). The product is mixed with the pulp from 16 and 18.

Other substances, such as cellulose in a ground or coarse condition maybe introduced at 21. The resulting mixed pulp may be conveyed into thickeners at 22 or subjected to other desirable treatment.

Claim The process of treating wood to make 5 paper-pulp, comprising grinding the wood, separating the knots, splinters and slivers from the chips, fiber and flour produced by the grinding, screening these latter constituents to separate the flour from the fiber and 10 chips, screenin the fiber and chips to separate the chips om the fiber, screening this latter fiber to separate therefrom the finer constituents, uniting the fiour from the first screening with the said finer constituents, 18 passing the residue from the second screening to another screening operation,separatingthe v chips from said residue, passing the resultant finer particles through a thickening operation, passing the product thence through a 20 beating operation to loosen and open the fiber bundles and render same pliable, mixing the gliablized fibers with the products of the rst and second screenings and mixing cellulose with this last mixture. 25 In testimony whereof I have signed my name unto this specification.

PER KLEM. 

